Some external signers scripts may provide master fingerprint in uppercase format. In that case core will fail with Signer fingerprint 00000000 does not match any of the inputs as it only works with lowercase format. Even if the fingerprints match, yet one is lowercase the other uppercase.
Core can instead normalize fingerprint from PSBT and check both upper/lower case hex representation
Very similar to #25019 but no changing of fingerprint from external signer.